
CY28547
.....................Document #: 001-05103 Rev *B Page 13 of 24
CPU_STP# Assertion
The CPU_STP# signal is an active LOW input used for
synchronous stopping and starting the CPU output clocks
while the rest of the clock generator continues to function.
When the CPU_STP# pin is asserted, all CPU outputs that are
set with the SMBus configuration to be stoppable via assertion
of CPU_STP# will be stopped within two–six CPU clock
periods after being sampled by two rising edges of the internal
CPUC clock. The final state of all stopped CPU clocks is
High/Low when driven, Low/Low when tri-stated.
Figure 5. Power-down Deassertion Timing Waveform
DOT96C
PD
CPUC, 133MHz
CPUT, 133MHz
SRCC 100MHz
USB, 48MHz
DOT96T
SRCT 100MHz
Tstable
<1.8 ms
PCI, 33MHz
REF
Tdrive_PWRDN#
<300
s, >200 mV
CPU_STP#
CPUT
CPUC
Figure 6. CPU_STP# Assertion Waveform
CPU_STP#
CPUT
CPUC
CPUT Internal
Tdrive_CPU_STP#,10 ns>200 mV
CPUC Internal
Figure 7. CPU_STP# Deassertion Waveform